A novel and modular strategy has been developed for the preparation of reactive and functionalized hydrogels. In this strategy, thiol-epoxy coupling chemistry was employed for the formation of a hydrophilic network. The hydroxyl groups, generated during the coupling process, were then engaged in anchoring a fluorescent probe to the hydrogel scaffold.

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A modular approach toward the synthesis of polymers containing dendron groups as side chains is developed using the Diels–Alder “click” reaction. For this purpose, a styrene‐based polymer appended with anthracene groups as reactive side chains was synthesized. First through third‐generation polyester dendrons containing furan‐protected maleimide groups at their focal point were synthesized. Facile, reagent‐free, thermal Diels–Alder cycloaddition between the anthracene‐containing polymer and latent‐reactive dendrons leads to quantitative functionalization of the polymer chains to afford dendronized polymers. The efficiency of this functionalization step was monitored using 1H and 13C NMR spectroscopy and FTIR and UV–vis spectrometry. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 410–416, 2010

A novel N-hydroxy succinimide-based carbonate monomer that allows direct synthesis of polymers incorporating a reactive carbonate group in the side chain was synthesized. This new monomer was copolymerized with methyl methacrylate and poly(ethylene glycol) methylether methacrylate using free-radical polymerization to obtain organo-and water-soluble reactive copolymers. Copolymerization of the activated carbonate monomer with an azide-containing monomer and N-hydroxy succinimide-containing activated ester monomer provided orthogonally functionalizable copolymers. The pendant reactive carbonate groups of the copolymers were functionalized with amines to obtain carbamates. Polymers capable of orthogonal functionalization could be selectively functionalized as desired using subsequent 1,3-dipolar cycloaddition or amidation reactions. The novel monomer and the copolymers were characterized by 1 H-NMR, 13 C-NMR, and infrared spectroscopy. The efficient stepwise orthogonal functionalization of the copolymers were examined via 1 H-NMR spectroscopy. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4737][4738][4739][4740][4741][4742][4743][4744][4745][4746] 2010

A combination of 'orthogonal' thiol-ene 'click' reactions is utilized for fabrication and functionalization of micro-patterned hydrogels. A furan-protected maleimide-containing parent copolymer is partially activated via the retro Diels-Alder reaction to obtain an 'orthogonally' functionalizable copolymer, where the different functional groups can be exploited for multi-functionalization or fabrication of functional hydrogels using combination of the nucleophilic and radical thiol-ene reactions.

Functional hydrogels that can be obtained through facile fabrication procedures and subsequently modified using straightforward reagent-free methods are indispensable materials for biomedical applications such as sensing and diagnostics. Herein a novel hydrogel platform is obtained using polymeric precursors containing the maleimide functional group as a side chain. The maleimide groups play a dual role in fabrication of functional hydrogels. They enable photochemical cross-linking of the polymers to yield bulk and patterned hydrogels. Moreover, the maleimide group can be used as a handle for efficient functionalization using the thiol–maleimide conjugation and Diels–Alder cycloaddition click reactions. Obtained hydrogels are characterized in terms of their morphology, water uptake capacity, and functionalization. Micropatterned hydrogels are obtained under UV-irradiation using a photomask to obtain reactive micropatterns, which undergo facile functionalization upon treatment with thiol-containing functional molecules such as fluorescent dyes and bioactive ligands. The maleimide group also undergoes conjugation through the Diels–Alder reaction, where the attached molecule can be released through thermal treatment via the retro Diels–Alder reaction. The antibiofouling nature of these hydrogel micropatterns enables efficient ligand-directed biomolecular immobilization, as demonstrated by attachment of streptavidin-coated quantum dots.

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Advances in several areas of contemporary biomaterial science are closely related to the design of stimuli‐responsive smart materials. An important aspect that governs widespread adaptation of a synthetic biomaterial depends on its ease of synthesis, as well as facile functionalization. In this study, readily available homo‐bifunctional PEG‐based diamines are mixed with a tetra‐arm epoxide based cross‐linker to yield hydrogels through the epoxy‐amine addition reaction. Hydrogels obtained with varying chain lengths of PEG polymer are characterized for their morphology, swelling, and rheological properties. The residual epoxide groups within the hydrogel are used for post‐gelation functionalization to obtain a functional material. In particular, functionalization with an amine‐containing rhodamine derivative yields a hydrogel that serves as a colorimetric sensor for acidic pH environment, and indicates the presence of Fe3+ cation with high specificity.